The present invention relates to a coupling that is insulated and that is used to couple together two opposing (pipe) flanges, which insulated pipe coupling comprises gripping and retaining elements for locking and securing the flanges when they are coupled together, wherein the insulating elements are connected to the flanges. Furthermore, the invention also relates to a pipe coupling apparatus comprising two pipe flanges and at least one pipe, as well as means for coupling together the two pipe flanges, wherein at least one of the pipe flanges is connected to a pipe.
In connection with different types of operations that are carried out during the offshore production of hydrocarbons, it will be necessary, for various reasons, to be able to connect and disconnect the equipment used. This may, for example, be the case for different equipment that is placed on the seabed, where components such as manifolds, pumps, pressure tanks etc. are connected via pipes and couplings, either to each other in a closed system, or also to one or more floating or fixed installations.
A pipe coupling that can be used in connection with aforementioned operations and/or conditions is described in NO 314 422. The pipe coupling is used to clamp together two pipe flanges and comprises fingers that are arranged along the periphery of the pipe flanges. When the pipe coupling is closed, the fingers are held in a locked position by means of a sliding ring which lies on the outside of the fingers. The sliding ring is moved in the longitudinal direction of the fingers by means of an actuator, which actuator may be arranged in the coupling itself or it may be arranged on an external subsea tool, for example, a remote-operated subsea vehicle (ROV).
In addition to the above loads, the deployed equipment, because of the depth or the waters in which it is deployed, will be exposed to seawater that is just a couple of degrees above freezing point. If the well, for example, is choked or closed off temporarily, the hydrocarbons that are in the tubing will be cooled to temperatures as low as the temperatures of the water, which may lead to hydrate formation in the equipment. This can result in the flow through the tubing being blocked or in the equipment being damaged.
To prevent hydrate formation in subsea equipment, U.S. Pat. No. 6,889,770 proposes a method and an apparatus which insulate subsea installations, this being done by encompassing the subsea installation in a housing. The actual installation of the housing is carried out in several steps and requires the use of divers, special equipment etc. During maintenance operations or the replacement of equipment or components that are within the housing, the housing must be removed from the subsea installation, the necessary maintenance and/or replacement carried out, after which the housing must be mounted in place again.
Furthermore, from US 2003/0168857, GB 1314816, GB 2296749 and US 2004/0178626 there are known different types of couplings which employ fingers that lock around opposing flanges.
One of the objects of the present invention will therefore be to provide an insulated pipe coupling, where the insulation that is arranged around the coupling is less complicated to install, and makes the coupling process easier.
Another object of the present invention is to provide a pipe coupling where the insulation takes up forces and/or loads to which the pipe coupling is subjected, particularly during installation.
Yet another object of the present invention is to provide an insulated pipe coupling that prevents hydrate formation in the insulated areas.
Still another object of the present invention is to provide an insulated pipe coupling where the insulation is mounted on the pipes before they are lowered to the seabed.
Yet another object of the present invention is to provide an insulated pipe coupling where the insulation protects the pipe flanges and an area around them from impacts, knocks or the like.
Still another object of the present invention is to provide an insulated pipe coupling, which coupling safely secures the coupled components.
Yet another object of the present invention is to provide a pipe coupling which can be operated, that is to say, both coupled and released, by a subsea vessel, for example, a ROV.